RESUMO
A family of genes of the agamic race of planarian Girardia tigrina were described that encode proteins that belong to the superfamily of C-type lectins and were demonstrated to have a unique domain organization. The genes are differentially expressed in the planarian body. The protein products of at least two genes (scarf2 and gtlec1) are expressed in specifically differentiated gland cells of the planarian and secreted into the environment through long cell necks. A comparison of the results obtained by electron microscopy and immunohistochemistry with literature data allows the assignment of these cells to the group of adhesion glands. The observation of the regeneration of the cell necks in normal and artificial two-headed planaria indicated that the dorsoventral contact at the edge of the head part of the planarian body directs and maintains the growth of the gtLec1-producing cell necks during regeneration. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.
Assuntos
Proteínas de Helminto/genética , Lectinas Tipo C/genética , Planárias/genética , Regeneração/fisiologia , Sequência de Aminoácidos , Animais , Proteínas de Helminto/metabolismo , Imuno-Histoquímica , Íntrons , Lectinas Tipo C/metabolismo , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Planárias/metabolismo , Planárias/ultraestrutura , Regeneração/genéticaRESUMO
A new method for finding differentially expressed genes, termed ordered differential display of mRNAs (ODD), was used in the search for region-specific molecular markers of freshwater planarian Dugesia tigrina. In this method, the effect of selective suppression of a polymerase chain reaction (PCR) is used for the differential amplification of a pool of 3'-terminal cDNA fragments generated by digestion of cDNAs with a restriction endonuclease. In the resulting amplified cDNAs, every mRNA is represented by a cDNA fragment whose length is determined by the position of the restriction site nearest to the 3'-terminus. Subsequent PCR with primers 3'-extended by two random nucleotides allowed the amplification of 1/192 part of all cDNA molecules present in the sample. The comparison of the generated pools of cDNA molecules separated by PAGE leads to the identification of differentially expressed sequences. The systematic study of the total mRNA pool is achieved by the successive use of all possible combinations of extended primers. Some sequences preferentially expressed along the anterior-posterior axis of planarian were identified using ODD.
Assuntos
Clonagem Molecular/métodos , Marcadores Genéticos/genética , Planárias/genética , Animais , Sequência de Bases , Primers do DNA , DNA Complementar , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
We identified two new genes (scarf and collar) of planarians using subtracting hybridization. mR-NAs of these genes are distributed in different ways in regeneration blastemas of different polarity. Zone-specific expression of these genes in non-regenerating planarians has been demonstrated. The level of expression of the identified genes in the head regeneration buds of the first-third days of regeneration was lower than that in the corresponding intact tissues and tail regeneration buds.
